orget the 9th Circuit.  Let's talk about the state with the lowest population:  Wyoming, about 180,000 voters in the 2014 general election.  So get about 90,000 hobbyists and providers to move there and form a third party.  Get a hobbyist elected as a governor.  Then the hobbyist-governor would simply pardon anyone charged with (or previously convicted of) prostitution

The hard part: getting anyone to move to Wyoming.